Bolt anchor



Dec. 26, 1933. A. w. GELPCKE BOLT ANCHOR Filed April 2, 1932 FIG. 2

' INVENTOR- ALFRED W: GELPCKE ATTORNEY- Patented Dec. 26, 1933 UNITED sTATEs PATENT OFFICE sour ANCHOR Alfred Gelpcke, Brooklyn, N. Y., assignor to The Rawlplug Company, Inc., New York, N. Y.

Application April 2, 1932. Serial No. 602,658

5Claims. (01. 72-105) which has many advantages as set forth in said patent.

My present invention is directed to a modified form of two-piece bolt-anchor so constructed as to be a unitary device, and one which may be reversibly installed in the hole made to receive it.

In the drawing,

Figure 1 is an end-view of the complete device.

Figure 2 is a part-elevational and part-sectional view of the same.

Figure 3 is an end-view of a modified form of the device.

Figure 4 is a part-elevational and part-sectional view of the modified form of the device.

By reference to the drawing, it will be seen that the bolt-anchor comprises a strip 1 of metal both ductile and malleable, arranged in the form of a spiral which is preferably substantially uniform in its diameter .from one end of the anchor to the other. Preferably the convolutions terminate in flat, parallel flanges 2 and 3. This spirally-arranged member may be made from rolled stock having the desired cross-sectional area, or it may be cast. In either case, itserves as a frame-,

work for carrying between the spirals an expansible metal 4 which is preferably of lead moulded into the spiral framework, but so as to leave a bore 5 through the anchorto receive a bolt or stud.

In the form shown in Figure 4, the spirallyarranged member 1 has a different cross-sectional area than that shown in'Figure 2, but otherwise what has been said with respect to Figure 2, ap plies to the anchor shown in Figure 4.

In Figure 4, however, the spirally-wound member 1 has its convolutions ending-in a' relatively sharp biting edge 6, which assists in causing the spiral to grip into the masonry or concrete as the device is hammered into position.

In the use of these unitary reversible anchors,

they are dropped into a hole in the masonry and hammered into gripping position in the manner set forth in my patent previously referred to, but

masonry, and likewise, the spirals themselves, as

they are driven together, also seize the side-walls of the hole and thereby function jointly with the expansible metal to make a secure connection between the anchor and the material in which they are placed.

I form'the frame-member 1 of aluminum, althoughI do not wish to be limited to thisparticular material, but since aluminum is light and has the necessary strength, it is admirably suited for the purpose and has the advantage of reducing the cost of shipping, as well as lightening the tool-bag of the workman, and is therefore preferable to use.

Having thus described my invention, what I claim is:

1. A bolt-anchor comprising a single spirallyformed member extending the full length of the anchor and terminating in flanges, and expansible metal lying between the spirals but leaving comprising a member formed in convolutions'to encircle a boltfor the normal length of the anchor, said convolutions having a relatively sharp biting edge and expansible metal between said convolutions.

4. A unitary two-piece bolt-anchor comprisinga spirally-arranged metallic frame having a continuous relatively sharp biting edge and adapted to be compressed and expansible metal carried by the spirals of the frame. r

5. A bolt anchor comprising a single spirallyformed member extending the full length of the anchor and terminating in flanges, and expansible metal lying between the spirals and forming therewith and with said flanges a central hole for a bolt, the inside and outside radii of the flanges, spirals and expansible metal being correspondingly the same.

' ALFRED W. GELPCKE. 

